Warning Notes
by Stop this insanity
Summary: At the end of each year, all the students of Hogwarts are given a warning note about underage magic.  This year, thanks to the Weasley twins, long held secrets are about to come to light.   Oneshot


**Warning notes.**

It was the final day of term at Hogwarts and Fred and George Weasley were in the common room.

Not their own common room mind you. They were in the Slytherin common room.

Having learnt about young Harry Potter's invisibility cloak from their somewhat less than discrete younger brother Ron, the two third years had instantly seen the pranking potential in such an item. (They had actually been trying to find out how to do the disillusionment charm for quite a while now. However, none of the professors or upper year students that they had asked aid from had been willing to try teaching them the sixth year spell. It was as if the whole school believed that a potentially invisible set of Weasley twins might be a rather bad thing.)

With their new information, though, they had immediately started making plans to convince Harry to occasionally lend them the cloak.

Which eventually, of course, led to the duo being in the heart of Slytherin territory. Going where no prankster had gone before; well except perhaps for their heroes the marauders.

Their plan had been simple. They had borrowed the cloak from Harry (Though managing to ask his permission whilst he had been in the hospital wing under the all seeing eyes of Madam Pomfrey had been quite the task.) and taken it with them (hidden beneath George's robes) to the leaving feast, feeling quite rightly that their absence at the feast would likely be noticed and remarked upon (if only by Perfect Percy the Prefect). After all, the whole goal of a successful prank was to have no-one able to later on prove that you did it.

The moment the feast ended, and students began to leave the hall, they were away. Racing through the corridors in an effort to reach the dungeons before any of the Slytherins.

They eventually reached their destination, and stopped to cover themselves with the cloak.

Easily entering the Slytherin common room, thanks to their map, they moved carefully into the room, trying to decide the best place to wait without being bumped into.

Once that was done, it would just be a matter of waiting until the Slytherins turned in for the night, and they could start their prank extravaganza. The snakes would never see it coming, unlikely as they were to be on guard from a Weasley Prank right here in their own lair. Better yet, getting here so early guaranteed that there wouldn't even be the chance of any observant snakes seeing the door to the common room mysteriously open and close on its own as they entered.

All they had to be concerned about for the next couple of hours was keeping out of the way of the scurrying. Not too big of a problem as it turned out. As was the normal situation in the Gryffindor common room, most of the Slytherins were off in their dorm rooms packing their trunks ready for the journey home the next day (The twins of course had planned ahead, and very sensibly packed their own trunks that morning.) which meant that there were very few Slytherins for them to avoid.

A very boring hour after the feast the door opened once again, both redheads tensed at the sight of Professor Snape entering the room, and simultaneously seemed to try and sink further back into the corner they were stood in.

Snape looked around the room until he spotted one of the Slytherin prefects.

"Mr. Wooller." said Professor Snape. "If you would please inform the first year students that I am waiting for them. Your presence will also be required for the first few minutes." Ian Wooller, the sixth year prefect looked up at hearing his head of house addressing him. His expression briefly confused at the order, before it changed to sudden realisation.

"Oh, it's time for THAT isn't it Sir. I'll fetch them right away Professor Snape."

Fred and George were confused. What was happening? What was this THAT that Wooller had referred to?

Before they had had much time to ponder the situation, the sound of footsteps signalled the approach of the Slytherin first years.

Entering the common room, they walked to where Snape was and stood in a neat row in front of him.

Professor Snape stood looking at the row of attentive and curious looking first years, as he prepared to begin his regular end of year speech.

"I have called you here today to give you some important information which will benefit you greatly during the rest of your time as a Hogwarts student." He began. "Before we go any further however, I will be requiring that each and every one of you make an unbreakable vow to never teach what you are about to learn to, nor discuss the subject with any non-Slytherin.

The twins pricked up their ears, suddenly a great deal more interested in whatever was about to happen. If this was information that the Slytherins didn't want anyone else to know, and they were willing to swear unbreakable vows just to make sure that others wouldn't get to know… well then, Fred and George DEFINITELY wanted to know what it was.

"Unbreakable vows?" Draco Malfoy's voice rose querulously above the noise of the suddenly chattering first years. Why should we have to swear unbreakable vows? We're first years. What could possibly be so important a secret that vows would be needed, but would still be getting told to first years?"

"I assure you Mr. Malfoy, that the vows are necessary. Though if you feel you do not wish to make the vow, and be privy to the secrets that you are all about to be told, then by all means return to your dormitory to complete your packing. After all, your Father, himself a Slytherin, would easily be able to teach you these things instead, though by that time, what you learn will be useless to you until the next year. Leave if you wish Mr. Malfoy, but do not expect your Father to be pleased by your squandering of this opportunity, and do not imagine that he would not ask for the same unbreakable vow."

Fred watched delightedly as Snape verbally cut down the arrogant Malfoy brat, wondering just how much Ron would have been willing to pay to watch that, then, as he and his twin silently watched the blond boy subside into sullen silence, realising that if Ron had been here, his cheers at the scene would have got them caught just then for sure.

"Now," Snape's smooth voice continued "if there are no more complaints or questions, we will proceed with the vows. Mr Wooller will be our bonder."

The twins watched as each of the Slytherin first years made a vow not to discuss with or teach to any non-Slytherin what they were about to learn. As each successive vow got performed, their curiosity grew about just what this secret could be.

When at last the vows were done, and Prefect Wooller dismissed from the common room, they eagerly listened as Professor Snape once again began speaking.

"As all of you no doubt know," he started, "all magical children have a charm that is known as a Trace applied to them. The sole function of this charm is to allow the ministry to tell when underage wizards are performing magic outside of a school environment, and allow them to properly enforce the Decree for the Reasonable Restriction of Underage Sorcery. The Trace breaks automatically when a child becomes of age. What is less well known, though over the years there are many students who have worked the method out, is how that trace is actually applied.

"When each of you first journeyed to Hogwarts, you had with you a ticket for the Hogwarts express. That ticket is actually issued by the Ministry of Magic, and is specially designed to apply the trace to its owner. When you first step foot on the school train, the spell work on the ticket activates and the trace is automatically attached to you.

"So if we hadn't used the tickets we wouldn't have got the trace now?" shrieked Pansy Parkinson. "If I'd known that, I wouldn't even have touched the thing. Why didn't any of our parents warn us?"

"My Mother actually even reminded me to bring the thing." Grumbled Blaise Zabini.

"Be quiet." Snape snarled. Stopping the impending heaping of blame upon the Slytherin parents before it could get fully started, and unknowingly doing the same with the somewhat uncharitable thoughts regarding a certain red haired ministry worker's potential culpability.

"IF you had not each had your ticket with you, you would not have been able to board the school train at all. In order to ensure that each child actually gets the charm applied to them when they first begin Hogwarts, every September the first, an age line is applied to all the entrances to the school train. Any child who is less than 12 years of age on that day - or in other words, first years – will be unable to pass the age line unless they have in their possession a ticket for the Hogwarts express. Once they have passed the age line, they have boarded the train and the enchantments on the ticket activate and attach the Trace to the child.

"The only way to avoid the process would have been to arrive at Hogwarts for your first year, without travelling on the train. However, any first year who does not take the train, will have a visit by a member of the Improper Use of Magic Office to have the Trace manually applied to them.

"There is no escaping the application of the Trace, though there have been several attempts over the years by those who learned about the methods in a timely manner.

There was, for instance, the attempt made in 1948 by one rather exceptionally bright Hufflepuff fifth year, who decided that even though she and her cohorts were beyond being helped, that she would 'save all those possible future puffs', and simply find a way to prevent any further first years from having the Trace applied to them.

Her attempt failed of course. As have all others both before and since." Snape paused a moment to allow what he had said so far to sink in, then with a nasty smirk, resumed speaking.

"And now we come to the actual reason behind your unbreakable vows. Because although you have all had the Trace applied to you, for the time that you are actually at the school, it is mostly undetectable.

Given the sheer amount of magic performed by students at school, the Improper Use of Magic Office would be overloaded with sorting through the reports if the Trace were to be active throughout the term time. To this end, the trace is attached to you, but is at such a low level, that the vast majority of the magic learned by pre-owl students is undetectable. For the ministry to actually be able to monitor your magic usage throughout the summer holidays, an extra element is required.

The doors of the London bound Hogwarts express are also spelled with an age line. This time, no student that is not yet of age will be permitted to board unless they are, once again, in possession of a specific object.

Before you leave the school tomorrow you will be handed a note to take home, warning you that you are forbidden to practise magic during your summer holidays. That note is the object required for you to be able to board the train home." Fred and George knew that note well. They had always hoped that maybe one year the school would forget to give them out to them all. Now if Snape was telling the truth, it turned out that they wouldn't forget to give them out, since none of the students would be able to go home. Though given what the potions master had revealed about the Hogwarts express train ticket – which they did note they had received in their first year, but then never again – both twins would be willing to bet their life savings that there was also some nefarious extra reason for those notes.

"As with your tickets at the beginning of the year, the warning notes are also heavily enchanted." Yep. Here came the nefarious reason. "The spells on the notes work with the Trace which is already upon you all. The moment you step aboard the train, the spells will act to enhance the trace, boosting its power to the point where even the smallest piece of magic being performed by you will be immediately detected by the Improper Use of Magic Office; resulting in action being taken against you by the ministry."

"I still don't get why we had to swear unbreakable vows just to get told this." Whined Malfoy, ignoring the glowering of the dark haired man at being interrupted again. Truth be told, neither did the Weasley twins. So okay, they had just discovered that the ministry of magic were bigger killjoys than they had ever before suspected, but really, was the news THAT Earth shattering?

"You will cease interrupting me when I am speaking Mr. Malfoy, else you will find yourself back in your dormitory and being excluded from the lesson that the rest of your year mates are about to have." Professor Snape's voice was dark and threatening as he addressed Malfoy. Draco Malfoy, upon looking up at the face of his head of house and seeing the promise of punishment there, immediately apologised before falling completely silent Standing up slightly straighter, and more at attention, under the forbidding gaze.

"Do not forget though, that we are Slytherins. If we do not like a particular situation, we will always find a way around it. Some method to make it work to our advantage. Because of this, unbeknownst to the ministry and the rest of the school, for the past 92 years, the students of Slytherin house have been able to perform magic during their summer holidays." The gasps, at that astounding piece of information, which came from the first year Slytherins at that point, fortunately covered up the quiet though still audible gasps of shock that the Weasley twins also gave. Almost a hundred years, and they had been keeping it quiet from the rest of the world for all that time. They just absolutely had to find out how the trick was done.

"How Professor Snape?" The question, voiced by one of the girls in the group, fell quietly into the long pause that had been left by the professor after his revelation.

"An excellent question Miss Bulstrode. Very soon after this method of using the notes forbidding the use of underage magic to actually catch the users of underage magic was begun, a charm was developed to counteract it. This charm, the Donse-May charm, has been secretly passed on through the students of Slytherin house ever since. At the end of each year, each successive group of first years is bound to secrecy and then taught the charm.

It is now your turns.

The Donse-May charm acts to mute the trace upon the caster completely, further even than the low level it is at during term times, and will work regardless of how greatly boosted it has been. Since it works only upon the caster of the charm, it cannot be cast upon you. It must be cast BY you, and must be done so at a point after the Trace upon you has already been boosted to its summer holiday level. Casting the Donse-May charm before your trace is enhanced is useless, since the moment you board the train it will be boosted to the point where the ministry will once again be able to detect it.

Even the most dim witted amongst you must now realise that the only possible viable chance that you will have to perform the charm is after you are already aboard the Hogwarts express.

The school train, just as the school is, is exempt from the laws against underage magic, and so you can still cast spells without consequence. Once you have reached Kings Cross however, all magic by underage wizards and witches becomes completely forbidden. Should you fail to correctly cast the Donse-May charm upon yourself by the end of the journey to London, you will not be able to try casting it again until the beginning of the next summer holidays, since any attempts will then be picked up on by the ministry.

Before I teach you all the charm, I will caution you all. Given your vows and the nature of this secret, the utmost discretion should be used when performing magic in the situation where there is even the remotest of chances of it being discovered by any non-Slytherins. This means that a great deal of prudence should be used by those of you with younger siblings (regardless of what house you are 'sure' they will be sorted into) and those of you with non-Slytherin parents or older siblings. If someone is not a current or past member of this house, you are NOT to allow them to discover any part of this secret.

This charm has been successfully kept secret by generations of Slytherins for almost a century. Believe me; you do NOT want to be the one who allows it to be revealed.

Now, watch carefully as I demonstrate the charm for you, then you will all practice it slowly whilst I correct any problems in your pronunciation or wand movements.

Fred and George knew just one thing at that moment, they wanted, no they NEEDED, to learn that charm.

As one, they edged slightly closer to the gathered group, trying to get as good a view as possible. They settled in to watching carefully, trying to take in every detail. They both knew that they would only have this one chance to learn the charm, without even being able to ask any questions or request help, after which they would have to wait until next year and try to sneak back in to the Snake pit to try again.

The secret lesson over with, Professor Snape dismissed the first years back to their dormitories to conclude their packing for the next day. Hearing the request for aid by one of the first year boys, the professor followed the group through to the boys' dormitories, leaving the two third year Gryffindors alone in the now empty common room.

Seeing their chance, George tugged on his brother's arm, and began moving towards the exit. All plans of staying and pranking the Slytherins after hours now abandoned. The two of them had something much more important to do, and it couldn't wait until after curfew.

After leaving the common room in the dungeons undetected, the pair were halfway back to Gryffindor tower before they stopped and began to compare notes on they should go about their next move.

Deciding that the first thing they should do was actually check that they had learned the charm, the duo hurried down a side corridor to where they knew there were a few unused classrooms. Once inside, they began practising.

"It's a good thing that the pair of us are such bright chaps George." Commented Fred after five attempts at the spell finally gained the brief red glow around his body that signalled a successful casting.

"That it is George." Agreed George, as he also managed to cast the spell correctly.

"Aren't you George?" Asked his brother, as he made a few more successful casts of the charm.

"I don't know. I thought I was being Fred today, wasn't I?" Asked George with a grin, also managing to cast the charm several more times.

"Maybe." agreed his brother. "For now we can both be George. We can both be Fred tomorrow, just to keep things even.

"Still," continued Fred, "there are a lot of students in this school who aren't nearly so good at picking up spells quickly, and if you're thinking what I'm thinking…"

"To teach them all the Donse-May charm," continued George, "We'd still be trying to work our way through them by the time we got to King Cross."

"So we need to get a small group from each house taught, and then have them teach all the others." Rationalised Fred.

"Prefects." Stated the pair in unison.

"So we just call in at the other house common rooms and collect up their prefects on our way back to Gryffindor." Decided George.

"Won't work." argued Fred. "We can't be the ones to ask all the prefects to come for a meeting. Our reputation precedes us Brother mine. If the invite comes from us, they'll suspect some sort of trick."

"Far too suspicious, they are." lamented George, though in complete agreement with his brother. "We'll just get a couple of the others on the Quidditch team to fetch them for us. They'll believe us enough to do it, and will be believed enough to get the Claws and Puffs to follow."

"Get the map out, we'll look up the other common room passwords for them whilst we're here. Then we can go back and send our messengers off to gather up all the prefects. No, wait, scratch that. We should ask for all of the prefects, but also anyone who has finished their packing."

"Good idea there brother. There are bound to be some, and that way there will be more skilled teachers to pass the charm on to the rest of their houses. After all, we're playing a serious game of catch-up here. The Slytherins only had to teach their first years, whilst we have to get every year taught."

The Gryffindor common room was full to bursting, not a spare seat or patch of floor to be seen. Not only was every Gryffindor present, but also over twenty assorted Ravenclaws and Hufflepuffs, who had been convinced into coming to this meeting by Oliver Wood and Katie Bell.

The Weasley twins had stood up in front of the group and told the tale of their evening's discoveries. Followed by the offer to teach their newly learned spell to all of those that were there listening. The din - with most of the occupants of the common room all trying to talk at the same time - that had followed the revelation of just how the ministry applied the trace, and the boost, was nothing compared to the shouting that had followed once they had reached the part of the tale telling how the entirety of Slytherin house all used a secret Slytherin-only charm to get around the rules that the rest of them were stuck having to obey. They had only been able to continue their story at that point through he use of sonorous.

"How do we know that this isn't a prank of some kind?" Asked one of the slightly more suspicious Ravenclaw prefects, raising the obvious question given just who the so helpful duo imparting all of this information was. "You're asking us to believe in some kind of major conspiracy by the Slytherins, involving unknown charms, a century of secrecy and unbreakable vows being taken by eleven year olds. Isn't it far more likely that this is actually just a joke being played upon three quarters of the school, where you will teach us some pretend charm and then sit back and laugh whilst a hundred and fifty students get official reprimands for underage magic?" The grumbling that followed the voicing of this theory showed that the Ravenclaw wasn't the only one thinking of that possibility. The twins looked at each other, they had considered that that this might happen, and knew that they would need to nip the suspicions against them in the bud right from the start. They sighed. Drastic measures then. As one, they drew their wands and raised them.

"I Fred Weasley,"

"I George Weasley," they intoned together,

"Do swear upon my magic, that to the best of my knowledge, everything that I have said tonight regarding the Donse-May charm is completely true."

Several dozen jaws dropped at the low flash of light which signalled the completion of the magical oath which had just been sworn by the Weasley twins. None of them could deny that they were telling the truth now.

"Look," began the twin that everyone now knew to be George Weasley, "we may play pranks, but we don't do stuff that would get anyone into serious trouble, and underage magic reprimands can lead to really serious trouble."

"But we really don't think that it's fair that all of the Slytherins can get to practise magic all they want through the summer, and we're stuck without." continued Fred. "So we teach all of you how to do the charm, then the Ravenclaws and Hufflepuffs go back to their houses and teach all the rest of them, and everyone is on a fair footing for the first time in nearly a century. Then we just have to have each year's seventh year prefects perhaps, to teach the charm to each year's new lot of firsties."

"The ministry puts those rules in place for a reason." Broke in one particular voice. Both twins rolled their eyes in exasperation. It figured it would be him. "Rather than having even more of us breaking the rules, it would surely be far better to just reveal what the Slytherins are doing so that the ministry can put a stop to it." Suggested Percy Weasley. By the looks on the faces of the others in the common room, it was obviously not a very popular suggestion.

"Shut up Weasley. It's not even a fair rule." Shouted one of the other onlookers.

"And you also have to think of yourself for a bit here Perce." Said George cajolingly. "You've just taken your OWLs haven't you, and I'm sure you got absolutely wonderful marks, just like always,"

"But how much better might they have been if you could have done magic?" Continued Fred. "We know that you spent as much time as you could studying last holidays, but no matter how much you studied, all that you could really do was read the theory. What if you could have practised the spells too? How much easier might you have found your exams?" Looking around the common room, George could see that all of the Ravenclaws present were also seemingly rather interested in this particular argument. He pressed on with trying to convince his older brother.

"And then of course there were your chores. How much extra time could you have had for your studying and homework each year if you had been able to use a couple of simple household charms to help with things like cleaning up. And how improved might your practical NEWT marks be in two years time if you've had an extra two summers to practise all of your spell work? It could be the difference between an outstanding and only an Exceeds Expectations."

"My Mum was in Slytherin." Wailed one of the sixth year Hufflepuff prefects suddenly. All these years of me not being able to do magic at home, and she knew about this charm the whole time."

"She probably wanted to be able to tell you too." Stated one of the Ravenclaws who was sat nearby. "But that's the trouble with an unbreakable vow. You're not a Slytherin. So regardless of how she felt, she could never tell you how to get around the trace."

"But… The rules…" protested Percy

It had taken a fair bit of convincing, and even a large number of threats, mostly from the Ravenclaws - and interestingly enough, a few rather frightening ones from the Hufflepuffs - eventually though, they were all agreed (including Percy) that they should all learn the Donse-May charm.

The twins had worked to teach the other houses first, since they had their own houses to teach and tell the story to, then worked on getting all of the Gryffindor prefects and upper years learning it, which much to their surprise, had included all the already of age seventh years (though they were mainly learning it to help teach it to their house faster). By the time that all of Gryffindor could say that they could easily perform the charm, it was two hours after curfew and many students still had to finish the last little bits of their packing.

Morning came, and with it an even more hectic rush of activity than usual for this time of year, due to so many more of the students than normal in the tower still having not finished their packing. However, the packing was all soon done and the students finishing up the final breakfast of the year, before each of them was handed their copy of the note warning them that they were forbidden to perform magic during the summer. Now knowing the true purpose of the warning notes, Fred and George, and many other watchful students on three house tables, for the first time noticed the smug smirks being bandied around at the Slytherin table. As if they believed that they knew some secret that the rest of the school didn't. For those watchers, (and several of their friends that they told later) any lingering doubts as to whether using the charm was the right thing vanished in that moment.

For the so called golden trio, this summer was looking like it might have end up being completely unlike any that they had ever had before. They were about halfway through the journey back to London, and all three of them had used the charm to mute the Trace. Travelling in companionable silence, their thoughts had already turned to the weeks ahead.

Ron was looking forward to all of the Quidditch he could play, due to now being able to finish most of his chores in record time with a few simple cleaning charms (when his parents weren't looking of course) that even a reluctant studier such as himself had picked up over the years of observing his mother.

Hermione, ardent studier that she was, was looking forward to being able to study ahead on practical work as well as just the theory. She was also already planning the small 'magic show' that she would now be able to give her parents, to demonstrate a little of what she was learning at Hogwarts.

Harry's thoughts were also on the subject of housework. Partway through the year, he had decided to try and learn a few household spells to maybe make his life a little easier when he went back to Privet Drive over the summer. Over the past few months he had started to build up a small repertoire of cooking cleaning and gardening spells that he felt might come in useful. Hearing that he might not have been able to use them had been a bit of a blow, as had the thought of not actually being able to use magic to frighten Dudley into leaving him alone again this summer. Now though… perhaps a simple levitation charm as he took his trunk up to his room. Just some simple reminder that Harry was now well able to do magic should get the Dursleys off his back a little.

By the time the Hogwarts express pulled into Kings Cross station, not one of the children on board would have failed to cast the charm on themselves.

As arranged the previous day, the Weasley twins were the first ones off the train. Once upon the platform, and therefore now subject to Decree for the Reasonable Restriction of Underage Sorcery, they both surreptitiously cast a tripping hex towards a couple of the Slytherin Parents.

As they all began to climb down from the train, almost every student in three Hogwarts houses waited anxiously for any signs of owls from the Improper Use of Magic Office. When it became evident that there weren't going to be any, the mood of three quarters of the entire school suddenly lifted, as all the under aged students suddenly knew that this was going to be their best summer ever.


End file.
